PURPOSE: To improve the straightness of the track of a rotating head on the lead by machining the lead and the fitting reference plane of a fixed drum in reference to a shaft.

CONSTITUTION: A fixed drum 1 which is provided with a lead 1a to run and guide a recording medium and a fitting reference plane 1b, a shaft 2 which is rotatably supported by the fixed drum 1 via ball bearings 6, 7, and a rotating drum which is attached to the shaft 2 and provided with a rotating head facing to the recording medium for transmitting and receiving signals are arranged. Then, the first and second cutting tools 28, 29 machine the lead 1a and the fitting reference plane 1b of the fixed drum 1 in reference to the shaft 2.